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KZN floods: Is it a consequence of climate change?

Ridge Rd in La Lucia, under the bridge to Armstrong Ave. Picture: Shelley Kjonstad/ African News Agency

Ridge Rd in La Lucia, under the bridge to Armstrong Ave. Picture: Shelley Kjonstad/ African News Agency

Published Apr 16, 2022

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The government has declared a provincial state of disaster in KwaZulu-Natal after the region was battered by almost a week of torrential rain which led to devastating floods and landslides which have claimed over 400 lives and counting, leaving complete and utter destruction in its wake.

Durban and its surrounding communities bore the brunt of the storm with bloated rivers sweeping away informal settlements, roads and bridges across the city.

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President Cyril Ramaphosa claims the disaster "is part of climate change", but many Durbanites blamed poor infrastructure for the scale of the flooding.

The weather system which triggered the floods led to in excess of 300mm of rainfall being dumped over a 24-hour period on 11 April. This is significantly more than the 165mm and 108mm which caused the April 2019 and October October 2017 floods.

According to the South African Weather Service (SAWS), the sheer amount of rain which fell on Monday was equal to about 75% of South Africa's average annual precipitation and would have resulted in some form of flooding without any other contributing factors, according to experts.

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This means that even if all of Durban’s stormwater drainage systems were clean and excellently maintained, there would still be flooding of some sort. The city’s infrastructure was just not built to withstand such an enormous amount of rain over such a short period of time.

Tafadzwanashe Mabhaudhi, from the University of KwaZulu-Natal said that the weather was typical of the type that develops off the coast of South Africa, involving moisture-laden warm air moving in from the Indian Ocean. The undulating hills of KZN cause the moist air to rise, and as it does so, it cools and forms rain clouds.

SAWS said the amount of rain was "of the order of values normally associated with tropical cyclones". It believes it is not correct to attribute individual weather events occurring over short timescales to longer-term trends, such as global warming.

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But experts at SAWS say severe and extreme weather events are becoming more frequent and more extreme as a result of climate change.

"In other words, heavy-rain events, such as the current incident, can rightfully be expected to recur in the future and with increasing frequency," the agency says.

The recently released Intergovernmental Panel on Climate Change report looked at storms in southern Africa earlier in 2022, and found that extreme rainfall in the region was becoming more common because of global warming.

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But it added that "the precise contribution of climate change could not be quantified, due to the absence of comprehensive historical records of rainfall".

Some residents have blamed the state of local infrastructure for the disaster, citing a lack of progress in improving drainage systems, as well as strengthening roads and poorly-built housing.

Durban's mayor, Mxolisi Kaunda, has rejected suggestions the city's drainage infrastructure is to blame, but did point to the fact that some houses have been built on steep hills without solid foundations.

"One of the factors to this disaster is a landslide in those areas," he says.

The Durban area is hilly and dissected with gorges and rivers, and it's true that hillsides are sometimes subject to landslides. But experts say that although the terrain is a contributing factor, poor urban infrastructure is also to blame.

"A combination of this rugged terrain, coupled with poor infrastructure, are factors to the flooding problem the city is experiencing," says Hope Magidimisha-Chipungu, an expert on town planning from the University of KwaZulu-Natal.

"Some of this infrastructure is old, it has surpassed its life span and needs to be replaced."

She says about a quarter of the city's population live in informal settlements - unplanned constructions which have been built on vacant land and then spread, and which are generally built with poor-quality materials.

"The materials used for building houses fail to keep weather elements at bay, hence the collapse of houses and loss of life in some cases," she says.

The Durban area population expanded after the end of the apartheid system in the 1990s. Before that, residence within the city had been restricted to white people only.

Between 1996 and 2001, official data shows the population within the municipality increased by 2.3% over the five-year period. The rate of population growth then slowed, but the city continued to expand. This put pressure on the existing infrastructure, which has failed to keep up.

Gina Ziervogel, an expert on climate change adaptation, from the University of Cape Town, says the authorities have been trying to address some of the challenges posed by the risks of climate change.

But she says more resources are needed, given the area's old and failing infrastructure and the new challenges posed by more extreme weather.

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